As of Release 4.0A, in addition to standard PO items you can settle returns items (new in 4.0A) via the evaluated receipt settlement (ERS) procedure.
You can set the "Evaluated receipt settlement" indicator separately for standard PO items and items with returns. This means that you can settle only PO items or only returns items with ERS, or you can use ERS for both.
If you have previously worked with ERS, only PO items were affected up to now. If you wish to continue working on this basis, there is nothing you need to do.
If you wish to work with ERS for returns items only or for PO and returns items, you must set the indicator in the vendor master record.